A search amongst prior patents has revealed numerous documents disclosing structures pertinent to the field. U.S. Pat. No. 3,431,410 to Dolan et al and, U.S. Pat. No. 3,532,874 to Rosenost both disclose a bundled group of optic fibers held together at one end. A light source is placed at the grouped end. The light travels through each fibre substantially without dispersing and emerges at the other end to produce a set of pin point like lights.
U.S. Pat. No. 1,921,614 to Fry Jr., U.S. Pat. No. 2,227,861 to Petrone and U.S. Pat. No. 3,465,139 to Segal all show elongated glass or lucite rods adapted to conduct light through the branches of a Christmas tree in order to provide bulb like Christmas lights for the tree.
U.S. Pat. No. 3,564,233 to Cox et al shows a system employing separately encapsulated optical fibre conduits which are branched off from a central optical fibre bundle which is positioned along the trunk of a Christmas tree. The light which is transmitted through the central bundle of fibers illuminates translucent shapes mounted on the terminal ends of the fiber.
The above mentioned structures do not provide what is referred to at line 49 of U.S. Pat. No. 3,766,376 has a spray like effect. Both U.S. Pat. Nos. 3,766,376 and 3,624,385 disclose structures which attempt to provide such a visual effect.
However, the structure described in U.S. Pat. No. 3,624,385 requires numerous electrical connections, while the structure disclosed in U.S. Pat. No. 3,766,376 requires a set of ties for tying the bundle of optical fibers to the trunk of the tree. Both the electrical connections and the ties are cumbersome and time consuming to install.
U.S. Pat. No. 3,766,374 discloses a decorative structure using optical fibers which are linked to structural rods while U.S. Pat. No. 3,878,503 discloses a structure using optical fibers which are confined and supported by a bendable wire spirally wound around a plurality of fibers.
The U.S. Pat. No. 4,364,102 to Huppert and Castoro discloses a structure which attempts to eliminate the need for structures required to bundle a mass of fragile optical fibers and eliminates the safety hazard ever present with the use of large amounts of electrical wiring to provide illumination, by providing an internally lighted Christmas tree which transmits the light to the exterior of the display.
The structure proposed by the present invention also eliminates the need for structural reinforcement. The new structure is adapted to produce the spray-like effect without the use of any specific complicated electrical wiring or structural reinforcement. The new structure uses "light pipes" which are both self supporting and bendable.
The entire length of the each fibre is specifically adapted to glow radially thus providing an enhanced visual effect. Furthermore, the present invention proposes a structure which can be readily customized in any shape, size and nature. The installation procedure is reduced to a single step operation.
Instead of proposing a fixed shape artificial tree as is the case with U.S. Pat. No. 3,465,139 and U.S. Pat. No. 4,364,102 which, once purchased, offer only a given shape and size and which proved to be relatively complex, the present invention offers a decorative structure which can create a variety of decorative pattern and which is adaptable to a variety of trees.
The present invention provides the spray light effect without the numerous connections of the structure described in U.S. Pat. No. 3,624,385 or the numerous ties required by the structure described in U.S. Pat. No. 3,766,376, thus facilitating installation. The present invention also eliminates the need for obstructing supporting structures such as the longitudinal rods of the structured described in U.S. Pat. No. 3,766,374 and the spirally wounded wires of the structure described in U.S. Pat. No. 3,878,503.
The invention utilized an optical principle often referred to as trans-illumination or more commonly, as a "light pipe". The phenomena is characterized by the fact that light rays introduced into one end of a relatively smooth article made of glass or certain type or transparent plastics such as P.M.M.A. will be transmitted therealong, without diffusion until the light rays encounter the translucent edge of the article or some other light diffusing obstruction. Theoretically, if the transparent light transmitting material is of uniform density, free from imperfections and the outer surface is relatively smooth, the light rays will not be visible when the article is viewed transverse to the path of travel of the light rays. However, the light rays will travel the length of the article and will illuminate the end thereof or any translucent obstruction which may defuse the rays. This is true irrespective of the colour of the light and a translucent obstruction placed in the path of the light will glow as if it were the source of light.
Glass and most clear plastics, especially those of the methyl methacrylate type, often designated as "lucite" process this end or edge lighting ability and may be used in the construction of the invention.
All the invention described in the above mentioned patents were intended to optimize the end lighting effect. The present invention departs from the spirit of these previously mentioned inventions by proposing a structure adapted to provide a radial diffusion transverse to the path of light along the entire length of each individual branch as well as an axial diffusion at the distal end of each branch.
Since the branches of the present invention are free from any obstructing structural reinforcing components, the radial glow of the branches create a pleasing asthetical effect along their entire length.
The invention is thus versatile, easy to install, structurally simple and asthetically optimal. It provides both a radial diffusion along the entire length of each fibre and an axial diffusion at a distant tip of each fibre which can be connected to a terminating structure which provides a bulb like effect.
These advantages are obtained by using a set of "light pipes" which are optimally sized and optically coupled to a suitable light source.
Most structures described in the previous patents used fibers having a diameter too small to provide the advantages offered by the present invention. Most of them used optical fibers which have a small diameter in order to ensure that the light rays are substantially parallel to the fibre thus minimizing refraction. These fibers are designed to carry light over a great axial distance. The use of fibers having a larger diameter by the present invention allows both structural sufficiency and enhance radial diffusion since some of the light rays will eventually reach the diffraction angle of the material. The larger fibers used with the present invention diffused large amounts of light and therefore a suitable high energy light source had to be optically connected to the fibers. Over the last few years the wide spread commercialization of the high energy light commonly referred to as halogen type lights has greatly reduced the cost of such light source. Contrarly to the structures described in the previously mentioned patents, the present invention thus uses a halogen type of light as its light source.
To further enhance the aesthetical effect provided by the present invention, taking advantage of the fact that the radial glowing occurs on the full length of each fibre, a set of segmented colored disc has also been developed. Although such discs have already been disclosed by previous patents namely U.S. Pat. No. 3,465,139, the invention proposes a set of discs having a specific colour segmentation adapted to further optimize the aesthetically pleasing effect created by the device.